Anterior Skull Base Approach Research Articles

Transpalpebral Eyelid Approach for Supraorbital Frontal Craniotomy and Access to the Anterior Cranial Fossa.

The transpalpebral eyelid approach is an innovative alternative to traditional incisions for exposure of the anterior cranial fossa for neurosurgery. However, there is a paucity of data on this surgical technique in the plastic surgery literature for accessing the anterior cranial fossa. A retrospective review was performed of patients who underwent supraorbital frontal craniotomy using an anterior skull base approach with transpalpebral exposure over 8 years by a single plastic surgeon. Surgical techniques, medical comorbidities, intraoperative complications, and long-term complications were assessed. Twenty patients (mean age 52 ± 12 years, 55% male, 45% female) underwent supraorbital frontal craniotomy using an anterior skull base approach with upper transpalpebral exposure. Operative indications included the following: 75% had anterior communicating aneurysms, with a mean aneurysm size of 5.36 ± 1.91 mm; 10% had meningiomas; 10% had dural fistulas; and 5% had an orbital hemangioma. A total of 60% of patients had a smoking history. No intraoperative complications were encountered, and no cases required conversion to a traditional open approach. Mean length of hospital stay was 3.2 ± 1.5 days. Postoperative imaging revealed no residual or recurrent pathology. Mean follow-up time was 62.2 ± 30.6 months. No long-term neurologic or ophthalmologic complications or infections occurred. No forehead paresthesias, brow ptosis, or brow paralysis were noted. The transpalpebral technique is a safe, minimally invasive method to approach lesions of the anterior cranial fossa. Successful application may require appropriate management of the frontal sinus and supraorbital nerve. This approach does not limit neurosurgical access or results and led to no neurosurgical complications. Therapeutic, IV.

Anatomy for Endoscopic Endonasal Skull Base Surgery

Endoscopic endonasal skull base surgery has become popular due to its minimally invasive nature to the patient and the development of various medical devices. The reason why it is considered less invasive is that it is possible to reach the anterior skull base lesion using the corridor of the nasal cavity and paranasal sinuses. The roles of the nasal sinuses include acting as breathing pathways, warming, humidifying, and filtering of inhaled air, olfaction, and being a resonant cavity, all of which are important for a comfortable life, and the loss of these functions reduces the quality of life. Therefore, to perform endoscopic endonasal skull base surgery in a minimally invasive and safe manner, it is necessary to understand the anatomy of the nasal sinuses to reach anterior skull base lesions while preserving nasal structures as much as possible. This article describes the normal local anatomy of the nasal cavity and the paranasal sinuses, as well as the surgical techniques, especially the anterior skull base approach and the pterygopalatine fossa approach, for endoscopic endonasal skull base surgery.

Maturation of the sella turcica and parasellar region: Surgical relevance for anterior skull base approaches in pediatric patients

ObjectiveTraditional and extended transnasal transsphenoidal approaches provide direct access to a variety of anterior skull base pathologies. Despite increased utilization of transnasal approaches in children, anatomic studies on pediatric skull base maturation are limited. We herein perform a surgically relevant morphometric analysis of the sella and parasellar regions during pediatric maturation. MethodsMeasurements of sellar length (SL), sellar depth (SDp), sellar diameter (SDm), interclinoid distance (ID), intercavernous distance (ICD), and the presence of sphenoid sinus pneumatization (SSP), and sphenoid sinus type (SST) were made on thin-cut CT scans from 60 patients (evenly grouped by ages 0–3, 4–7, 8–11 12–15, 16–18, and >18 years) for analysis. Data were analyzed by sex and age groups using t-tests and linear regression. ResultsSella and parasellar parameters did not differ by sex. SL steadily increased from 8.5 ± 1.2 mm to 11.5 ± 1.6 mm throughout development. SDp and SDm increased from 6.0 ± 0.9 mm to 9.3 ± 1.4 mm and 9.0 ± 1.6 mm to 14.4 ± 1.8 mm during maturation, with significant interval growth from ages 16–18 to adult (p < 0.01). ID displayed significant growth from ages 0–3 to 4–7 (18.0 ± 2.4 mm to 20.7 ± 1.9 mm; p = 0.002) and ICD from ages 0–3 to 8–11 (12.0 ± 1.8 mm to 13.5 ± 2.1 mm; p < 0.001), without further significant interval growth. SSP was not seen in patients < 3, but was 100% by ages 8–11. SSTs progressed from conchal/presellar (60% at ages 4–7) to sellar/postsellar (80% at adulthood). ConclusionThe sella and parasellar regions have varied growth patterns with development. Knowledge of the expected maturation of key anterior skull base structures may augment surgical planning in younger patients.

Treatment of traumatic cerebrospinal fluid rhinorrhea via extended extradural anterior skull base approach

ObjectiveTo describe and assess the repair technique and perioperative management for cerebrospinal fluid (CSF) leak resulting from extensive anterior skull base fracture via extradural anterior skull base approach. MethodsThis was a retrospective review conducted at the Department of Neurosurgery of the Shanghai Tenth People's Hospital from January 2015 to April 2020. Patients with traumatic CSF rhinorrhea resulting from extensive anterior skull base fracture treated surgically via extended extradural anterior skull base approach were included in this study. The data of medical and radiological records, surgical approaches, repair techniques, peritoperative management, surgical outcome and postoperative follow-up were analyzed. Surgical repair techniques were tailored to the condition of associated injuries of the scalp, bony and dura injuries and associated intracranial lesions. Patients were followed up for the outcome of CSF leak and surgical complications. Data were presented as frequency and percent. ResultsThirty-five patients were included in this series. The patients’ mean age was 33 years (range 11–71 years). Eight patients were treated surgically within 2 weeks; while the other 27 patients, with prolonged or recurrent CSF rhinorrhea, received the repair surgery at 17 days to 10 years after the initial trauma. The mean overall length of follow-up was 23 months (range 3–65 months). All the patients suffered from frontobasal multiple fractures. The basic repair tenet was to achieve watertight seal of the dura. The frontal pericranial flap alone was used in 20 patients, combined with temporalis muscle and/or its facia in 10 patients. Free fascia lata graft was used instead in the rest 5 patients. No CSF leak was found in all the patients at discharge. There was no surgical mortality in this series. Bilateral anosmia was the most common complication. At follow-up, no recurrent CSF leak or meningitis occurred. No patients developed mucoceles, epidural abscess or osteomyelitis. One patient ultimately required ventriculoperitoneal shunt because of progressive hydrocephalus. ConclusionTraumatic CSF rhinorrhea associated with extensive anterior skull base fractures often requires aggressive treatment via extended intracranial extradural approach. Vascularized tissue flaps are ideal grafts for cranial base reconstruction, either alone or in combination with temporalis muscle and its fascia---fascia lata sometimes can be opted as free autologous graft. The approach is usually reserved for patients with traumatic CSF rhinorrhea in complex frontobasal injuries.

Surgical Relevance of Pediatric Anterior Clinoid Process Maturation for Anterior Skull Base Approaches.

Removal of the anterior clinoid process (ACP) can expand anterior skull base surgical corridors. ACP development and anatomical variations are poorly defined in children. To perform a morphometric analysis of the ACP during pediatric maturation. Measurements of ACP base thickness (ACP-BT), midpoint thickness (ACP-MT), length (ACP-L), length from optic strut to ACP tip (ACP-OS), pneumatization (ACP-pneumo), and the presence of an ossified carotico-clinoid ligament (OCCL) or interclinoid ligament (OIL) were made from high-resolution computed-tomography scans from 60 patients (ages 0-3, 4-7, 8-11 12-15, 16-18, and >18 yr). Data were analyzed by laterality, sex, and age groups using t-tests and linear regression. There were no significant differences in ACP parameters by laterality or sex, and no significant growth in ACP-BT or ACP-MT during development. From ages 0-3 yr to adult, mean ACP-L increased 49%, from 7.7 to 11.5 mm. The majority of ACP-L growth occurred in 2 phases between ages 0-3 to 8-11 and ages 16-18 to adult. Conversely, ACP-OS was stable from ages 0-3 to 8-11 but increased by 63% between ages 8-11 to adult. Variations in ACP morphology (OCCL/OIL/ACP-pneumo) were found in 15% (9/60) of scans. OCCL and OIL occurred in patients as young as 3 yrs, whereas ACP-pneumo was not seen in patients younger than 11 yrs. The ACP demonstrates stable thickness and a complex triphasic elongation and remodeling pattern with development, the understanding of which may facilitate removal in patients <12. Clinically relevant ACP anatomic variations can occur at any age.

Application of hybrid cranioendoscopic approaches in anterior skull base surgery.

Anterior skull base approaches have included endoscopic or open microsurgical approaches for intracranial pathologies. However, discussion of a combined hybrid, cranioendoscopic approach, leveraging the benefits of both techniques, has been limited. Here we describe a case of a combined endoscopic, endonasal, and open microsurgical frontotemporal approach for resection of a complex anterior skull base lesion. A 62-year-old man with a large meningioma extending intradurally through the cribiform plate and sphenoethmoidal sinuses underwent a cranioendoscopic resection. Surgical techniques, including repair of the anterior skull base defect as well as complication avoidance and the coordination of multiple surgeons, are discussed.The video can be found here: https://youtu.be/Ti9tUUdWgJc.

Microsurgical Anatomy Review of Bifrontal Limited Transbasal Approach – Quantitative and Anatomy Study

The bifrontal transbasal approach is an anterior midline skull base approach to anterior skull base, sellae region and, if needed, to posterior skull base in the midline, often used for tumoral lesions but also useful for vascular or infectious pathologies. Descriptive anatomic study, 5 formalin-fixed human cadaveric heads were used injected with colored silicone. The dissection was made step-by-step to describe every anatomic structure encountered. The working distance was obtained from the posterior wall of the frontal sinus with and without orbital rim to the pituitary stalk, the sellae, the pontomedullary sulcus, and the anterior margin of the foramen magnum. Stepwise anatomic dissection was performed dividing the surgical technique into 6 stages: soft-tissue stage, bone stage, sinus stage, clival stage, intradural, and measurements. The objective of making the supraorbital osteotomy was to improve the vision over the neural structures without brain retraction and limited to the midline supraorbital rim to avoid aggressive manipulation and injury to the orbit. The working distances measured with the orbital rim were on average: to the pituitary stalk, 70.5 mm; to the sellae, 81.3 mm; to the pontomedullary sulcus, 97 mm; and the foramen magnum, 99.5 mm. Without the orbital rim measures were: to the pituitary stalk, 57 mm; to the sellae, 62.5 mm; to the pontomedullary sulcus, 96 mm; and the foramen magnum, 98.5 mm. The addition of osteotomies including removing of the orbital rim improves the access to the central skull base with special benefits on the working distances to the sellae region.

S1-18 NOVEL TRANSPALPEBRAL “EYELID” APPROACH FOR SUPRAORBITAL FRONTAL CRANIOTOMY AND ACCESS TO THE ANTERIOR CRANIAL FOSSA

Introduction: The transpalpebral “eyelid” approach is a novel alternative to the traditional incisions for supraorbital frontal craniotomy and access to the anterior cranial fossa. Using the natural skin folds of the eyelid, the transpalpebral incision mitigates visible scars to improve post-operative aesthetic outcomes. While this type of approach has been described in the neurosurgery literature, this is the first report of such a surgical technique in the plastic and reconstructive surgery literature for accessing the anterior cranial fossa. Herein, we elucidate our unique surgical technique and results for this approach to the anterior cranial fossa. Methods: A retrospective review was performed of patients who underwent supraorbital frontal craniotomy using an anterior skull base approach with transpalpebral exposure over seven years by a single plastic surgeon (D.A.S.). Surgical techniques, medical co-morbidities, intra-operative complications, and long-term complications were assessed. Pre- and post-operative imaging were evaluated. Results: Nineteen patients (mean age 52±12 years, 52% male, 48% female) underwent supraorbital frontal craniotomy using an anterior skull base approach with upper transpalpebral exposure. In terms of operative indications, 80% (15) had anterior communicating aneurysms with a mean aneurysm size of 5.36±1.91 mm, 10% (2) had meningiomas, 5% (1) had a dural fistula, and 5% (1) had an orbital hemangioma. Notably, 58% (11) had a smoking history. No intra-operative complications were encountered, and no cases were converted to traditional open approaches. Mean length of hospital stay was 3.3±1.5 days. Post-operative imaging revealed no residual or recurrent aneurysms, meningiomas, fistulas, or hemangiomas. Mean follow up time was 47.1±28.4 months. Long-term complications were limited to two patients requiring re-operation for aesthetic considerations related to palpable hardware with no further sequelae. Specifically, one patient had removal of right cranial hardware and cranioplasty with bone paste as well as temporalis muscle flap advancement, and one patient had removal of left cranial hardware and cranioplasty with bone cement. No long-term neurological complications or infections occurred. Conclusion: In conclusion, this transpalpebral technique is an excellent, minimally invasive, and innovative alternative to approach lesions of the anterior cranial fossa. This transpalpebral approach provides dissection in well-defined anatomical planes, affords preservation of the frontalis muscle, avoids injury to the facial nerve branches, and yields superior aesthetic outcomes to traditional craniotomy incisions.

Alternative Transpalpebral “Eyelid” Approach for Supraorbital Frontal Craniotomy and Access to the Anterior Cranial Fossa

PURPOSE: The transpalpebral “eyelid” approach is a novel alternative to the traditional incisions for supraorbital frontal craniotomy and access to the anterior cranial fossa. Using the natural skin folds of the eyelid, the transpalpebral incision mitigates visible scars to improve postoperative esthetic outcomes. Although this type of approach has been described in the neurosurgery literature, this is the first report of such a surgical technique in the plastic and reconstructive surgery literature for accessing the anterior cranial fossa. Herein, we elucidate our unique surgical technique and results for this approach to the anterior cranial fossa. METHODS: A retrospective review was performed of patients who underwent supraorbital frontal craniotomy using an anterior skull base approach with transpalpebral exposure over 7 years by a single plastic surgeon (D.A.S.). Surgical techniques, medical comorbidities, intraoperative complications, and long-term complications were assessed. Pre- and postoperative imaging were evaluated. RESULTS: Nineteen patients (mean age, 52 ± 12 years, 52% male, 48% female) underwent supraorbital frontal craniotomy using an anterior skull base approach with upper transpalpebral exposure. In terms of operative indications, 80% (15) had anterior communicating aneurysms with a mean aneurysm size of 5.36 ± 1.91 mm, 10% (2) had meningiomas, 5% (1) had a dural fistula, and 5% (1) had an orbital hemangioma. Notably, 58% (11) had a smoking history. No intraoperative complications were encountered, and no cases were converted to traditional open approaches. Mean length of hospital stay was 3.3 ± 1.5 days. Postoperative imaging revealed no residual or recurrent aneurysms, meningiomas, fistulas, or hemangiomas. Mean follow-up time was 47.1 ± 28.4 months. Long-term complications were limited to 2 patients requiring reoperation for esthetic considerations related to palpable hardware with no further sequelae. Specifically, 1 patient had removal of right cranial hardware and cranioplasty with bone paste and temporalis muscle flap advancement, and 1 patient had removal of left cranial hardware and cranioplasty with bone cement. No long-term neurologic complications or infections occurred. CONCLUSION: In conclusion, this transpalpebral technique is an excellent, minimally invasive, and innovative alternative to approach lesions of the anterior cranial fossa. This transpalpebral approach provides dissection in well-defined anatomical planes, affords preservation of the frontalis muscle, avoids injury to the facial nerve branches, and yields superior esthetic outcomes to traditional craniotomy incisions. Furthermore, this novel approach does not limit neurosurgical access or results and led to no neurosurgical complications.

Bifrontal Craniotomy for Resection of Recurrent Fibrous Dysplasia: 2-Dimensional Operative Video.

Fibrous dysplasia, which causes tumor-like growth and weakening of the involved bone, may require neurosurgical intervention to achieve complete resection with subsequent reconstruction. The case described in this video involved a 31-yr-old woman with a history of fibrous dysplasia who had previously undergone extensive craniofacial fibrous dysplasia resection and vault reconstruction. She presented to the emergency department with 1 wk of fever, chills, headache, sinus pain, and proptosis of her right eye. On examination, she had left gaze palsy and diplopia on left lateral gaze. Magnetic resonance imaging (MRI) revealed a right frontal lobe parenchymal abscess and progression of her fibrous dysplasia. Blood cultures were obtained, and treatment with broad-spectrum antibiotics and antiepileptics was initiated. The patient underwent a bifrontal craniotomy with extended transbasal anterior skull base approach for the resection of recurrent fibrous dysplasia, evacuation of the cerebral abscess, and placement of an external ventriculostomy drain. She tolerated the procedure well and was discharged on postoperative day 6 with intravenous antibiotics. Postoperative computed tomography and MRI demonstrated excellent resection of the skull base fibrous dysplasia with placement of soft tissue and fat flap in the surgical defect, decrease of right-sided proptosis, and drainage of the right frontal parenchymal abscesses. Three months later, the patient underwent placement of a custom-made Medpor cranioplasty implant (Stryker, Kalamazoo, Michigan). At her last follow-up appointment, 14 mo after surgery, she had complete resolution of the diplopia and gaze palsy. Neuroimaging demonstrated a small residual of fibrous dysplasia on the left frontoethmoidal recess. The patient gave consent for publication.Watch now at https://academic.oup.com/ons/article-lookup/doi/10.1093/ons/opy027 {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Bifrontal Craniotomy for Resection of Recurrent Fibrous Dysplasia: 2-Dimensional Operative Video","caption":"","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_sn3qh8og"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} Disclosure The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.

Quantitative Analysis of Transnasal Anterior Skull Base Approach: Report of Technology for Intraoperative Assessment of Instrument Motion.

To develop a method to measure intraoperative surgical instrument motion. This model will be applicable to the study of surgical instrument kinematics including surgical training, skill verification, and the development of surgical warning systems that detect aberrant instrument motion that may result in patient injury. We developed an algorithm to automate derivation of surgical instrument kinematics in an endoscopic endonasal skull base surgery model. Surgical instrument motion was recorded during a cadaveric endoscopic transnasal approach to the pituitary using a navigation system modified to record intraoperative time-stamped Euclidian coordinates and Euler angles. Microdebrider tip coordinates and angles were referenced to the cadaver's preoperative computed tomography scan allowing us to assess surgical instrument kinematics over time. A representative cadaveric endoscopic endonasal approach to the pituitary was performed to demonstrate feasibility of our algorithm for deriving surgical instrument kinematics. Technical feasibility of automatically measuring intraoperative surgical instrument motion and deriving kinematics measurements was demonstrated using standard navigation equipment.

An Automated Methodology for Assessing Anatomy-Specific Instrument Motion during Endoscopic Endonasal Skull Base Surgery.

Objectives Describe instrument motion during live endoscopic skull base surgery (ESBS) and evaluate kinematics within anatomic regions. Design Case series. Setting Tertiary academic center. Participants A single skull base surgeon performed six anterior skull base approaches to the pituitary. Main Outcomes and Measures Time-stamped instrument coordinates were recorded using an optical tracking system. Kinematics (i.e., mean cumulative instrument travel, velocity, acceleration, and angular velocity) was calculated by anatomic region including nasal vestibule, anterior and posterior ethmoid, sphenoid, and lateral opticocarotid recess (lOCR) regions. Results We observed mean (standard deviation, SD) velocities of 6.14 cm/s (1.55) in the nasal vestibule versus 1.65 cm/s (0.34) near the lOCR. Mean (SD) acceleration was 7,480 cm/s 2 (5790) in the vestibule versus 928 cm/s 2 (662) near the lOCR. Mean (SD) angular velocity was 17.2 degrees/s (8.31) in the vestibule and 5.37 degrees/s (1.09) near the lOCR. We observed a decreasing trend in the geometric mean velocity, acceleration, and angular velocity when approaching the pituitary ( p < 0.001). Conclusion Using a novel method for analyzing instrument motion during live ESBS, we observed a decreasing trend in kinematics with proximity to the pituitary. Additional characterization of surgical instrument motion is paramount for optimizing patient safety and training.

A minimally invasive anterior skull base approach for evacuation of a basal ganglia hemorrhage

We describe the technical nuances of a minimally invasive anterior skull base approach for microsurgical evacuation of a large basal ganglia hematoma through an endoport. Patients who suffer from large spontaneous intracerebral hemorrhages (ICH) of the basal ganglia have a very poor prognosis. However, the benefit of surgery for the management of ICH is controversial. The development of endoport technology has allowed for minimally invasive access to subcortical lesions, and may offer unique advantages over conventional surgical techniques due to less disruption of the overlying cortex and white matter fiber tracts. A 77-year-old man presented with a hypertensive ICH of the right putamen, measuring 9cm in maximal diameter and 168cm3 in volume. We planned an endoport trajectory through the long axis of the hematoma using frameless stereotactic neuronavigation. In order to access the optimal cortical entry point at the lateral aspect of the basal frontal lobe, a miniature modified orbitozygomatic skull base craniotomy was performed through an incision along the superior border of the right eyebrow. Using the BrainPath endoport system (NICO, Indianapolis, IN, USA), the putaminal hematoma was successfully evacuated, resulting in an 87% postoperative reduction in ICH volume. Thus, we show that, in appropriately selected cases, endoport-assisted microsurgery is safe and effective for the evacuation of large ICH. Furthermore, minimally invasive anterior skull base approaches can be employed to expand the therapeutic potential of endoport-assisted approaches to include subcortical lesions, such as hematomas of the basal ganglia.

The Expanding Spectrum of Disease Treated by the Transnasal, Transsphenoidal Microscopic and Endoscopic Anterior Skull Base Approach: A Single-Center Experience 2008–2015

The transsphenoidal approach was initially developed in neurosurgical practice as an operative approach to the pituitary gland. The introduction of the operating endoscope has improved the versatility of the transsphenoidal approach, broadening the spectrum of lesions that can be treated effectively with this operative strategy. We performed a retrospective review of all patients who underwent transnasal, transsphenoidal operations at Brigham and Women's Hospital from April 2008 to February 2015 and categorized each case by pathologic diagnosis. A total of 792 transnasal, transsphenoidal operations (512 endoscopic) were performed by 9 neurosurgeons for 33 pathologies over a 7-year period. Pituitary adenomas (535, 67.55%) were the most common impetus for a transsphenoidal operation. Others included Rathke cleft cysts (86, 10.86%), craniopharyngiomas (25, 3.16%), lympocytic hypophysitis/pituitary inflammation (21, 2.65%), arachnoid cysts (8, 1.01%), spindle cell oncocytoma (4, 0.51%), colloid cysts (4, 0.51%), and pituicytoma (2, 0.25%). Pituitary hyperplasia was treated in 9 cases (1.14%) and pituitary apoplexy in 7 (0.88%). Nineteen operations were undertaken for postoperative repairs (2.40%) and 3 for abscesses (0.38%). Other diseases treated transsphenoidally included chordomas (12, 1.52%), metastases (9, 1.14%), meningiomas (5, 0.63%), clival lesions (4, 0.51%), germinomas (3, 0.38%), granulomas (2, 0.25%), dermoid tumors (2, 0.25%), and 1 (0.13%) each of esthesioneuroblastoma, granular cell tumor, Wegener granulomatosis, olfactory neuroblastoma, glioneuronal tumor, chondromyxoid fibroma, epidermoid, meningoencephalocele, aneurysm, neuroendocrine carcinoma, chondrosarcoma, and lymphoma. Although initially devised in neurosurgical practice for tumors of the pituitary gland, developments in technology now make the transsphenoidal approach an effective operative strategy for a wide range of anterior skull base lesions.

A single-port operator-controlled flexible endoscope system for endoscopic skull base surgery.

In a human cadaver study, a single-port operator-controlled flexible endoscope (Flex® System), facilitated with a high-definition camera and two accessory channels was tested for skull base surgery. Skull base surgery was performed on human cadavers (n=4) using the Flex® System. A modified surgical midfacial approach, performed by rigid standard tools, was used for access to the sinus system, the skull base, and the middle cranial fossa. Endoscopic skull base visualization with the Flex® System is feasible. Surgical procedures performed included extended sinus surgery, anterior skull base approach, and visualization of the brain stem in the posterior cranial fossa. Important landmarks of the anterior skull base were visualized and manipulated by flexible compatible tools. The Flex® System allows for manipulation of the anterior skull base and visualization of the posterior cranial fossa in a preclinical setting. Further studies as well as development of supplemental tools are in progress.

Endonasal Anterior Skull Base Surgery: Pathologies, Results, and Complications

Objective: The increasing application of extended transsphenoidal approaches for a variety of indications mandates continued improvements in our understanding of anterior skull base approaches and their limitations. We performed a retrospective review of our experience with a spectrum of disease conditions treated by an extended endonasal endoscopic, or combined microscopic, anterior skull base approach.

Principles of anterior skull base resection: Open and endoscopic techniques

Resection of a neoplasm is the most common indication for an anterior skull base approach. This surgery aims to obtain a complete extirpation (with negative histologic margins) yielding the best oncologic outcome, while producing the least degree of functional and cosmetic morbidity. Open or endoscopic endonasal routes, or both, may be used for the resection based on the tumor stage, histology, and patient's specific needs and characteristics, as well as the surgeon's training and preference. Traditional open craniofacial approaches require a craniotomy and maxillofacial osteotomies that include those necessary for a subfrontal approach. This technique remains one of the primary strategies to manage anterior cranial base lesions, especially those with significant extension or involving critical neurovascular structures. A significant recent development in cranial base surgery is the adoption of endonasal endoscopic approaches, which have been applied to resect the anterior cranial base. Its benefits include the minimal manipulation of the brain (no retraction), avoidance of maxillofacial osteotomies, and lack of cosmetic deficits. Endoscopic, endoscopic-assisted, and open approaches afford advantages and disadvantages and have different indications and limitations; therefore, the skull base surgeon (or the skull base surgery team) must be versed in all techniques.

The Efficacy and Safety of Preoperative Lumbar Drain Placement in Anterior Skull Base Surgery

This study assesses the efficacy of preoperative lumbar drain (LD) placement prior to elective open cranial and endoscopic anterior skull base (ASB) surgery in reducing postoperative cerebrospinal fluid (CSF) leak. A retrospective review of 93 patients who underwent LD placement at our institution between 2006 and 2011 was performed. Of these patients, 43 underwent elective LD placement prior to ASB surgery; 2 patients had evidence of CSF rhinorrhea prior to surgery, and 41 had no evidence of a preoperative CSF leak. Of those 41 patients, 2 developed CSF rhinorrhea (2/41= 4.9%) as a result of surgery—all in our endoscopic patient population (N = 21; 2/21= 9.5%). No postoperative CSF leaks were noted in our open ASB surgery cohort (N = 20). Other complications were rare, but we encountered two instances of delayed malignant cerebral edema in the open ASB cohort that are discussed in detail. Overall, preoperative LD placement was found to be an effective means of preventing postoperative CSF leaks after ASB approaches, but potential and significant intracranial complications may occur in select patients that merit careful consideration prior to LD placement.

Surgical Management of Juvenile Nasopharyngeal Angiofibroma Using Lateral Rhinotomy: Study of 80 Cases

A series of 80 patients with histopathologically confirmed juvenile nasopharyngeal angiofibroma were treated surgically over a period of ten years (1995–2004). The lateral rhinotomy approach was used to expose the tumor and its extensions. Lateral rhinotomy with its extensions provides wide exposure of and access to the nose, nasopharynx, paranasal sinuses, pterygopalatine fossa, infratemporal fossa and temporal fossa. Most intracranial, extradural extensions can also be approached. There were no major operative or post-operative complications. Longterm follow up from one to ten years showed only 8 recurrences. The added advantage of this approach is that it can be combined with all the other anterior and lateral skull base approaches. The cosmetic outcome is satisfactory if nasal aesthetic subunits are taken into considerations while making the incision. The lateral rhinotomy approach is the most direct route to the body of the tumor and can be used to approach all the possible extensions of the tumor.

Avoiding Disaster at the Skull Base: Case Studies in 3D

Program Description: Disaster awaits unprepared surgeons at the skull base. Multiple routine surgeries in otolaryngology are in close proximity to the skull base. Potential risks of endoscopic sinus surgery include cerebrospinal fluid leak, loss of olfaction, penetrating brain injury, visual loss, hemorrhage from the internal carotid artery, and loss of trigeminal sensory and motor function. Potential risks of temporal bone and lateral approaches include vascular injuries of the sigmoid sinus, jugular bulb, and internal carotid artery; injury to cranial nerves 7-12; cerebrospinal fluid leak, intra- and extradural hemorrhage; and brain trauma. A thorough understanding of skull base anatomy is essential for avoiding such complications during routine surgical procedures. In this miniseminar, case studies will be used to demonstrate potential risks of standard surgical procedures relative to the skull base. Important anatomical landmarks and relationships will be presented in 3D using cadaveric dissections and intraoperative photographs. Strategies to avoid skull base complications will be discussed with an emphasis on everyday surgical procedures. Educational Objectives: 1) Understand key anatomical relationships at the skull base. 2) Relate skull base anatomy to anterior and lateral skull base approaches. 3) Apply anatomical knowledge to avoid surgical complications.